A Mothership is a large command and construction starship which forms the basis of a major fleet. Losing the Mothership results in Mission Failure, however, if the player has a Carrier in Multiplayer, then control is switched to the Carrier.
As it is the central ship in all fleets, it is able to construct almost any sort of starship. Given enough time and available resources, a Mothership could create an entire fleet from scratch, thanks to the Phased Disassembler Array technology employed in the construction bays, and would be capable of maintaining a command structure for this fleet. Motherships include resource drop-off points, long-range and short-range sensors, usually but not always engines and the all-important hyperspace module.
A fleet is commanded by a large sort of mothership which functions both as a flagship and as a mobile shipyard. While these vessels do not have particularly practical applications in regular space warfare the implications are that the invention of the hyperdrive makes the mobility of a large stationary object like the Mothership possible and the advances made in engineering that allow Capital Ships to be produced in mere weeks make a mobile shipyard very useful on the battlefield, constantly replenishing vessels lost in battle, reconstructing an entire squadron of fighters in perhaps a week and a frigate in days.
Homeworld focuses around the story of one particular fleet and its Mothership, that of the Kushan. That is to say, the Mothership as it is often referred to or the "Banana" as many fans jokingly call it thanks to its curved and elongated shape. This Mothership, of immense size (far larger than most Mothership-class vessels) was actually designed as a colony ship, not as a weapon or mobile ship factory. Its purpose was changed due to events that unfolded as the story moved along.
In Homeworld: CataclysmEdit
In the stand-alone expansion pack Homeworld: Cataclysm, the idea of large motherships was dispensed with, on the basis that the main characters of the story in Homeworld: Cataclysm would not be able to afford such a massive vessel or have the resources to operate it. In fact, the ad-hoc 'mothership' of the game--the Kiith Somtaaw Explorer-class Deep Space Mining Vessel Kuun-Lan--was built within the original game's Mothership. For most of Cataclysm's story, Somtaaw fleets resort to using carrier groups not dissimilar to modern-day aircraft carriers and their escorts. These carriers vary in design though most follow the original design used in Homeworld by the Mothership Fleet. The Mothership from the original game is converted into a space station manned by a skeleton crew.
In Homeworld 2Edit
In Homeworld 2 the Kushan Mothership returned, or the basic design so to speak. Though the actual Mothership in Homeworld 2 a fair bit larger than the one used in the original Homeworld its design is obviously inspired by the original and its name Pride of Hiigara reflects the Kushan pride in their homeworld. Its purpose now is for something that cannot be supported by a mere scattering of carrier groups, for it is to carry the bulk of the fleet on a single mission to stop the enemy.